This project is a case-control study in the epidemiology of nasopharyngeal carcinoma (NPC) in Malaysian Chinese. It will be based at the University of Illinois at Urbana-Champaign where data analyses will be performed, and at the University of Malaya, Kuala Lumpur, the Malaysian fieldsite. The objective is to investigate suspected occupational risk factors for NPC (particulates and gasses),l cigarette smoking, and alcohol use, and their interactions with the now established risk factors of dietary salted fish, and ethnicity. The specific aims are to: 1) test the hypothesis that occupational exposure to specific dusts, smokes, formaldehyde, and aromatic hydrocarbons in Selangor Malaysia are risk factors for NPC; 2) to estimate risk of NPC attributable to occupational dusts, smokes, and formaldehyde, dietary salted fish, alcoholic drinks, and cigarette smoking; and 3) to establish the size distribution of atmospheric particulate matter by weight in occupational dusts and smokes and the chemical concentrations of formaldehyde and aromatic hydrocarbons in typical worksites of NPC patients. The study will identify all histologically confirmed Chinese NPC patients diagnosed in the State of Selangor between January 1987 and July 1991. The aim is to interview 300 case participants matched as pairs to 300 control participants. Area samples of atmospheric particulate matter and personal breathing zone samples of formaldehyde and three aromatic hydrocarbons will be taken from 50 worksites where NPC case participants had worked. Field work in Malaysia will proceed from April 1990 until December 1991, and data analyses in Illinois until December 1992. Validation of occupational dusts and smokes, and dietary salted fish as risk factors for NPC would provide convincing evidence for the advisability of health education and regulation in occupational exposures to air pollutants in Malaysia, and elsewhere in Southeast Asia, and for similar interventions in maternal an child health programs to reduce the consumption of salted fish, especially in childhood. Information on the physical and chemical characteristics of worksite air pollutants is needed to plan laboratory studies to investigate possible carcinogenic mechanisms.